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1,4‐Dihydropyrrolo[3,2‐ b ]pyrrole and Its π‐Expanded Analogues
Author(s) -
Janiga Anita,
Gryko Daniel T.
Publication year - 2014
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201402367
Subject(s) - pyrrole , indole test , electrophilic substitution , chemistry , combinatorial chemistry , reactivity (psychology) , electrophile , electrophilic aromatic substitution , electrochemistry , solid state , computational chemistry , stereochemistry , organic chemistry , medicine , alternative medicine , electrode , pathology , catalysis
Various approaches to the synthesis of 1,4‐dihydropyrrolo[3,2‐ b ]pyrroles are summarized. Many two‐ and three‐step reaction sequences have been developed, and have allowed access to a broad variety of structures, including not only the parent 1,4‐dihydropyrrolo[3,2‐ b ]pyrroles, but also their π‐expanded analogues. The newest approaches are critically compared with older strategies. The reactivity of these compounds is also reviewed, with special emphasis on electrophilic aromatic substitution. The synthesis of indolo[3,2‐ b ]indole derivatives has been the subject of intense investigation. Overall, a few interesting and ingenious approaches toward these ladder‐type heteroacenes have been proposed, reaching total yields in the region of 30 %. Finally, the optical, electrochemical, and other physicochemical properties are presented in the broader perspective of heteropentalenes. The parent 1,4‐dihydro‐pyrrolo[3,2‐ b ]pyrroles constitute the most electron‐rich, simple, aromatic heterocycles, and their simple derivatives and π‐expanded analogues possess strong violet, blue, or green fluorescence both in solution and in the solid state.